In order to guard against forgeries or falsifications and in order to increase the security level, it is known to use security elements applied on the surface or introduced hulk-wise or as window(s) into a secure item, for example a label, a packaging, especially for medicines, foods, cosmetics, electronic parts or spare parts.
The secure item may in particular be chosen from among a payment means, such as a banknote, a bank card, a check or a restaurant voucher, an identity document such as an identity card, a visa, a passport or a driver's license, a secure card, a lottery ticket, a transport pass or else an entry ticket for shows.
Effects of masking of interlaced images by a revealing raster allowing, when the revealing raster and the image are superposed, the observation of an image by displacing the revealing raster with respect to the image or by changing the angle of observation, are known from patent applications EP 2 367 695, EP 2 585 308 and EP 2 586 014 and from patent EP 2 454 102.
However, these patents present interlaced images in the form of solid lines.
Also known from patent application EP 2 740 607 is a system comprising a revealing raster, a layer exhibiting pigments orientable by an external magnetic field and a magnetic layer exhibiting a raster of North and South poles, the revealing raster and the raster of North and South poles being of different colors. WO 2014 096 794 describes a first raster on which a second surface raster is embossed, the raster lines of the first raster exhibiting one and the same color in visible light and different colors when they are observed under a combination of visible light and invisible light and the two rasters being such that the device exhibits a different color, according to the angle of observation, when it is exposed to a combination of visible light and invisible light.